physiology notes 1 ( Glucocorticoids )

                   Adrenal Glands 

•  Divide into 2 parts : 

      - cortex   -> secrete glucocorticoid + mineralcorticoid + androgens
      - medulla -> secrete epineprine, norepineprine and dopamine.

• synthesis ( cortisol ) : * adrenocortical = steroid = use cholesterol from LDL 

    i - formation of cholesterol ester from LDL : 

        x- binding LDL to its receptor by endocytosis

        x- then the cholesterol are sterified and stored in the cytoplasmic vacoule

  ii - action of ACTH hormone in cortisol synthesis :

       x- ACth bind to its receptor = activate adenyl cylase = increase CAMP

       x- CAmp activate Ptn Kinase A to change Cholesterol ester -> cholesterol ( enzyme lipase)

       x- Cholesterol transported into mitochondria then change into cortisol ( cholesterol - pregnenolone - 17a OH pregnenolone - 11 deoxycortisol - cortisol ) 

** 17a OH pregnenolone to 11 deoxycortisol ( in the cytosol )

      x- cortisol are transport out 

• Actions : * can be specifically divide into 3 

         - permissive : non-directly but in small amount induce other hormone to function

         - physiology : effect in normal amount to normal body function

              i - metabolism : 

                  carbohydrates - it increase gluconeogenesis n inhibit glycolysis except in brain and heart

                 protein - catabolic ( inhibit ptn sythesis )

                 fat - increases lipolysis to supply energy  n increase ketone body

            ii - Appetite : increse intake of calories

           iii - CVS : maintain normal ABP

            iv - Kidney : increase Glomerular Filteration Rate = rapid water excrete

             v - CNS

            vi - Blood cell : increase in number but depress action / decrease in no ( T-lymphoct & eosinophill )

           vii - Stress : Acth secretion , activate symphathetic system

         - pharmacological : in excess of the cortisol it will acts antigonist enzyme : inhibit bone formation, inihibit CT production,Anti-inflammatory,Anti-allergy & Supress immunity and lymphoid tissue. 

• control of glucocortiocoid secretion : 

    i - Hypothalamo-pituitary-adrenal axis : action controlled by ACTH hormone ( CNS page 75 )

   ii - Negative feedback - cortisol( excess)  acts inhibitor to the ACTH and CRH

  iii - Circadian rhythm - physiological clock by suprachiasmatic nucleus * high rate in morning

  iv - Stress : stress increase secretion

  v - Vasopressin,serotonin and Vaso Intestinal peptide stimulate cortisol

p/s : harap maaf la jikalau x lengkap ke  terkurang info ke  @ tersalah fakta..lau ada tersalah jgn malu2 nk kritik tp jgnla kutuk..sekadar inisiatif dr kami unit subjek physiology.